Stimulated-source-independent persistent luminescence phosphor Sr2Ta2O7:Tb3+, Tm3+ for multi-mode anti-counterfeiting applications

Abstract

There is great interest in advancing optical anti-counterfeiting technology for use in information security, but the emission colors of traditional anti-counterfeiting phosphors vary depending on the stimulation source, which diminishes the difficulty of counterfeiting. Persistent luminescence (PersL) phosphors are particularly suitable for anti-counterfeiting applications because of their multimodal luminescence features. Herein, a PersL phosphor Sr₂Ta₂O₇:Tb³⁺, Tm³⁺ exhibited emission independence from the stimulation source, and emitted stable and reliable blue-green luminescence in down-conversion luminescence, PersL, up-conversion luminescence, and photo-stimulated luminescence. Depending on the multimodal luminescence features of Sr₂Ta₂O₇:Tb³⁺/Tm³⁺ phosphors, numerous patterns were successfully obtained to confirm its excellent anti-counterfeiting ability. This work illustrates the potentiality of the stimulated-source-independent multi-mode anti-counterfeiting long-lasting phosphor Sr₂Ta₂O₇:Tb³⁺/Tm³⁺ as a viable strategy for developing highly secure materials.